1. Field of the Invention
The present invention relates to optical apparatuses for capturing spectral images, and in particular, relates to a technology for acquiring spectral information on living bodies and the like using etalon elements.
This application is based on Japanese Patent Application No. 2006-141382, the content of which is incorporated herein by reference.
2. Description of Related Art
In a technology (for example, see the specification of Japanese Patent No. 2802061), wavelength characteristics of observation light or illumination light can be changed by using an etalon element capable of changing gaps between a plurality of optical members using driving means formed of piezoelectric elements and disposed in at least one of an imaging optical system and an illumination optical system disposed at the leading end of an endoscope.
Spectral information on living bodies and the like can be acquired using this technology disclosed in the specification of Japanese Patent No. 2802061.
The etalon element disclosed in the specification of Japanese Patent No. 2802061 includes the driving means formed of the piezoelectric elements disposed between two or more optical members. Since the etalon element changes the transmission characteristics thereof using an optical interference effect, it is necessary to reduce the gaps between adjacent pairs of the optical members to approximately the coherence length of light beams or less, and at the same time, the driving means for transferring the optical members requires high driving resolution.
In order to efficiently adjust the gaps between adjacent pairs of the optical members to the coherence length of the light beams or less, moving distances of driving sections need to be increased. However, it is difficult to increase the moving distances of the driving sections in the structure disclosed in the specification of Japanese Patent No. 2802061 having the driving means disposed between two or more optical members.